Release date editable on iTunes if they are audiobook

General Discussion
#1

If the file media type are Audiobook, you can change YEAR(Release Date) tag on iTunes to YYYY-MM-DD format from YYYY format.
Has someone already knew?

I use iTunes for Windows version 12.3.3 (64bit)

#2

I think the proper field would be RELEASETIME.
YEAR by standard has only 4 digits.